Door latch and lock of magnetic type



June 23, 1970 P.' R. GRAHAM DOQR LATCH AND LOCK 0F MAGNETIC- TYPE 2Sheets-Sheet 1 Filed Sept. 3, 1968 6-1L Fig.3

INVENTOR. Percy R Gra ham ATTOpIVEY 30 Fig.3A

Ill

June 23, 1970 GRAHAM 3,516,701

DOOR LATCH AND LOOK OF MAGNETIC TYPE Filed Sept. 3, 1968 2 Sheets-Sheet2 lNVENTO/I; Fig/2 By erdy 1?. 61'0 am H77'0PNEY United States Patent OUS. Cl. 292-144 8 Claims ABSTRACT OF THE DISCLOSURE A bolt containing amagnetized rotor member is longitudinally movable within a housingbetween a retracted position in which it is locked whenever the door isopen and a door locking position in which it is within a magnetizedstrike member. A ball or pin locks the bolt in both its retracted andoutwardly projected positions. The rotor and strike member aremagnetized so that, as the door is moved to a closed position, theirflux will first rotatively move the rotor and unlock the retracted bolt,then move the rotor and bolt endwise into the strike member locking thedoor closed, then lock the bolt in the strike member by furtherrotatively moving the rotor. A pull back link unlocks the bolt, retractsit and leaves it locked in the retracted position when the door is open.

BACKGROUND OF THE INVENTION Field of the invention My invention relatesto a latch and lock of a type in which a bolt is magnetically moved to alocked position when the door by which it is carried is closed and thislock and latch is in the nature of an improvement on the latches andlocks disclosed in my two prior Pats. No. 3,129,968, issued Apr. 21,1964, and No. 3,273,925, issued Sept. '20, 1966.

SUMMARY OF THE INVENTION General objects of my present invention are toimprove latches and locks of the type having magnetically operatedbolts, to reduce to a minimum the number of parts in said latches andlocks, to make them more tamper proof and to make them neater inappearance and less expensive to manufacture.

Another object is to provide a latch and lock in which a longitudinallymovable magnetically operated bolt is locked in an outwardly projectedposition in a strike member when the door by which it is carried isclosed and is locked in a retracted position when said door is open.

Another object is to provide a latch and lock embodying a tubularhousing having in it a trackway shaped so as to provide two spaced apartshoulders with which a track follower, herein disclosed as a ball orpin, and which is movable in the trackway, can engage to lock a tubularbolt in either a retracted or an outwardly projected position, the bolthaving within it a magnetized rotor member and said bolt beinglongitudinally movable into and out of a recess in a magnetized strikemember, the track follower being connected with and moving with therotor member and operating through a transverse slot in the bolt, thebolt normally being locked retracted when the door is in an openposition and the rotor and strike member being magnetized in such amanner that when the door is moved from an open to a closed position,their magnetic flux will unlock and release the bolt from its retractedposition by rotatively moving the rotor, then draw the bolt into therecess in the strike member and then lock the bolt against unauthorizedretraction from the strike member, such as by tampering or pickingmethods, by further imparting rotation to the rotor member.

Other objects of the invention will be apparent from the followingdescription and accompanying drawings.

3,516,701 Patented June 23, 1970 "ice BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a longitudinal sectional view of my lock and the strike memberwith which it cooperates showing fragments of a door and door jamb inwhich they are installed and showing the bolt of the lock in engagementwith the strike member.

FIG. 2 is a partly exploded view, partly in section and partly inelevation, of this latch and lock mechanism.

FIG. 3 is a top plan view looking down at the exploded parts as they areshown in FIG. 2.

FIG. 3A is a fragmentary sectional view showing a track follower in theform of a pin instead of a ball and which functions as a bolt lockingmeans.

FIG. 4 is a detached outer end View, taken on line 4-4 of FIG. 2, andshowing the strike engaging outer end of a tubular bolt.

FIG. 5 is a detached view showing the outer end of a lock housing as itappears before face plates are attached to it.

FIG. 6 is a detached elevational view, taken on line 6-6 of FIG. 2 andwith parts omitted, showing the inner end of a housing.

FIG. 7 is a detached plan view of a magnetized rotor member.

FIG. 8 is an outer end view of said rotor member looking in thedirection indicated by line 8-8 of FIG. 7.

FIG. 9 is an inner end view of said rotor member looking in thedirection indicated by line 99 of FIG. 7.

FIG. 10 is a view, partly in elevation and partly in section, of atorque member supporting ring and torque member supported by it.

FIG. 11 is an elevational view of said ring and torque member looking inthe direction indicated by broken line 1111 of FIG. 10.

FIG. 12 is a detached assembly view showing the top edge of a boltretracting or pull back link having on it a guide washer and acompression spring and having a cross pin in one end thereof.

FIG. 13 is a view partly in section and partly in elevation looking inthe direction of line 1313 of FIG. 12.

FIG. 14 is a somewhat schematic view showing in elevation a magnetizedstrike assembly and in section a magnetized rotor and a bolt andillustrating the operation of the magnets in rotatively moving the rotorand longitu dinally moving the rotor and bolt when the door is movedfrom an open to a closed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT This lock comprises an outercylindrical metal housing or casing 20 adapted to be installed in abored hole 21 in the edge portion of a door 22. The housing 20 has anarrow outwardly extending flange 23 on its outer end, FIGS. 1, 2, 3 and5, and said flange 23 is trapped and held between two face plates 24 and25 when the lock is fully assembled and ready for installation in thedoor 22. The face plates 24 and 25 can be secured together in anysuitable manner and can be attached to the door by screws 26. The innerend of the housing 20, see also FIG. 6, has an inwardly extending flange27 which is notched at two diametrically opposite locations so as toleave an opening of the shape shown on FIG. 6 and is provided at thenotched locations with two anchor lugs 28 which protrude from the end ofsaid housing 20. A transverse groove 29 is provided in the outer side ofeach anchor lug 28.

A longitudinally extending trackway, indicated in a general way by 20'in FIG. 3 and more fully hereinafter described, is provided in the wallof housing 20. For purpose of illustration this trackway is shown as aslot but it will be understood that the major portion of said trackwayis preferably in the form of a groove in the inside of the housing Wall.

A tubular bolt 30 fits snugly within the housing and is longitudinallymovable in said housing. The bolt 30 is approximately cup shape, iscylindrical throughout the major portion of its length, has a closedouter end 31 and has a flat portion 32 on one side thereof extendingfrom its closed outer end toward its inner end for about one half of itslength. A short transverse slot 33 is provided in the wall of the bolt30 about mid way of its length for registration with the trackway 20' inhousing 20, as hereinafter explained. The inner end of bolt is open toreceive other parts of the latch and lock mechanism. Preferably tubularbolt 30 is formed of strong durable material, such as nylon plastic or anon-magnetic metal.

A rotatively movable member, indicated generally by numeral 35 in FIG.7, is disposed within the tubular bolt 30 and is herein termed amagnetized rotor. Said rotor 35 is formed of an outer end part 36 and aninner end part 37 rigidly attached together by suitable adhesive or bymechanical means, such as screws. The inner end part 37 of rotor 35 canbe either metal or plastic. The outer end part 36 is a magnet more fullyhereinafter described. Said outer end part 36 has a flattened side 38which operates within the flattened end part 32 of the bolt 30. The twoflattened end parts 32 and 38 are suitably shaped to provide for limitedrotary movement of the rotor member 35 within the bolt member 30. Theinner end of the inner rotor part 37 has within it a recess or cavitycomposed of an axial bore 40 and two diametrically opposite notches orgrooves 40, FIG. 9. A longitudinally movable bolt operating pull backlink 41 extends into the bore 40 and is provided with a cross pin 42.The cross pin 42 is not attached to the rotor part 37 but moves freelyin the grooves 40'. The end of the link 41 remote from the cross pin 42extends through a suitable opening 43, FIG. 13, in a washer 44 andterminates in two divergent arms 45. Any suitable pull back means, suchfor instance as member 46, shown fragmentarily in FIG. 1, and which canbe operated by a knob or key can be connected with arms 45 forretracting link 41.

The washer 44 rests against the inner end flange 27 of housing 20 and isrigidly staked to said housing 20 by preferably two or more inwardlydisplaced parts 47. A stop member 48, FIGS. 1, 2 and 12, is rigid withlink 41 near the arms 45 and outwardly from washer 44 and will engagewith said washer 44 and limit inward movement of the link 41 relative tothe housing 20. A helical compression spring 49 on link 41 betweenwasher 44 and cross pin 42 yieldingly urges link 41 to the left, FIG. 1.

A torque member supporting sleeve or disc 50 is disposed within andyieldingly connected with the inner end portion of the tubular bolt 30and has an open center 51 which provides working clearance for link 41and spring 49. The disc 50 carries a torque member which is formed ofspring material and comprises an arcuate base part 52, a spring arm 53inclined away from the base part 52 and a torque arm 54 which isapproximately perpendicular to the base part 52. Preferably the disc 50is shaped to provide a marginal flange 55 on its inner side and the base52 of the torque member fits like a snap ring within this flange 55 andis rigidly attached to the disc 50 to hold it in proper adjustment atall times. The torque arm 54 extends generally parallel to the link 41alongside of the coil spring 49 and past the cross pin 41 into one ofthe notches 40' in the rotor part 37 and is positioned so it can bepressed against a side wall of said notch to exert an off center torqueon the rotor and rotatively move said rotor.

When the rotor 35 and bolt 30 are in the outwardly projected position,FIG. 1, the cross pin 42 will be close to the spring arm 53 and if thepull back link 41 is retracted it will first deflect the spring armtoward the disc 50 and in so doing will cause the torque arm 54 toimpart rotary movement to the rotor 35 and release the rotor 35 and bolt30 for retractile movement. Further retraction of link 41 will then movethe rotor and bolt to a fully retracted position. Preferably spring arm53 is indented at 53' to receive cross pin 42. Also preferably the faceof disc 50 is suitably shaped so spring arm 53 will be deflected flushwith disc 50 and both arms of cross pin 42 will press against disc 50 inretracting bolt 30.

The trackway 20" in the housing 20 is adapted to receive a trackfollower and locking member, shown in FIG. 1 as a ball 56 seated in aspherical depression 39 in rotor part 37. Ball 56 extends through thetransverse slot 33 in bolt 30 and into trackway 20'. Said trackway 2.0is herein disclosed as being in the form of a slot in the wall ofhousing 20 but preferably all parts of said trackway except an opening60 at the end thereof shown at the left in FIG. 3 will be in the form ofa groove in the inside wall of the housing 20. A locking pin 56, FIG.3A, can be used instead of the ball 56 by suitably modifying the shapeof a recess 39' in a rotor part 37 and if necessary modifying the shapeof a trackway 20b in a housing 20a. The purpose of the opening 60 at oneend of trackway 20' is to permit insertion of the track follower, suchas ball 56 or pin 56' in assembly.

In addition to the opening 60 the trackway 20' comprises a straighttrack portion 61 extending from the opening 60 longitudinally of housing20 and terminating in a locking shoulder 62 and another straight trackportion 63 transversely ofiset relative to track portion 61 and whichterminates in an enlarged portion 64 shaped to form a locking shoulder65. The locking ball 56 normally operates in the track portion 63,secures the bolt in locking position when it is engaged with shoulder 62and secures the bolt in retracted position when it is engaged withshoulder 65, as will be more fully hereinafter explained.

Preferably one or more small magnets, such as magnets 70 and 71, FIGS.'3 and 5, are attached to the housing 20 near its outer end andpositioned so the magnetic flux of their poles will react with themagnetic flux of the poles of magnetized rotor part 36 in exerting alight torque on rotor 35 urging and tending to hold the track follower,such as locking ball 56 or pin 56', against the shoulder 65. Obviouslyone only of the magnets 70 or 71 can be used but the use of two or moremagnets spaced around the rotor provides a better balance of forces.These small magnets lessen the danger of the bolt 30 being releasedaccidentally or as a result of tampering and moving to an outwardlyprojected position while the door is open. The holding force of smallmagnets 70 and 71 is overcome by a stronger magnetic force, ashereinafter described, when the door is moved to a closed position.

The strike means used in connection with this lock, FIGS. 1 and 14,comprises a strike plate 66, preferably of non-magnetic material, suchas nylon plastic, aluminum or the like, having in it a bolt receivingopening 67 and having back of it a strike magnet 68 forming a bottom forthe opening 67. The strike magnet 68 and strike plate 66 are installedin a suitably mortised recess in the door jamb 69. Preferably the wall67', FIG. 14, which forms the bolt engaging side of the strike plateopening 67 is convergently beveled from its outer edge toward its bottomso the bolt 30 will wedge against said inclined wall 67 when the door isclosed thereby providing a tighter fit and helping to prevent rattlingof the door.

A preferred method of assembling this lock is as follows: Insert therotor 35 in the tubular bolt 30, insert the disc 50 with attached torquemember 52, 53, 54 into the open end of bolt 30 and fixedly secure saiddisc 50 in the proper position in said bolt 30. Put washer 44 and coilspring 49 on pull back link 46 and insert cross pin 42 in link 46.Insert the cross pin carrying end of link 46 through the opening in thedisc 50. This is done by holding spring 49 retracted, and with link 46held at an angle to bolt 30, inserting one end of the cross pin 42through opening 51 in disc 50 and then manipulating the other end ofcross pin 42 through said opening 51 as the link 41 is moved intoalignment with the bolt 30. The assembled parts are then inserted intothe housing and manipulated so as to align the recess 39 in rotor member37, the slot 33 in bolt and the opening 60 at the end of trackway 20 inhousing 20 and the ball 56 is inserted. The bolt 30 and housing 20 arethen further telescoped together until the washer 44 rests against theend flange 27 of the housing where it is rigidly staked in place by theindentations 47 in the housing Wall. The ball 56 follows the part 61 oftrackway 20' until it rests against the shoulder 62, after which saidball 56 operates between the shoulders 62 and 65 along part 63 oftrackway 20'. The face plate assembly is applied to and made fast to theouter end of the housing 20 after the bolt 30 with rotor therein hasbeen inserted in said housing 20.

The rotor magnet 36 and strike magnet 68 are selectively magnetized asillustrated in FIG. 14. When the door 22 is in an open position thetubular bolt 30 and rotor 35 will be held by the ball 56 in a retractedposition. As the door 22 is moved to a closed position the flux of thetwo magnets 36 and 68 will first rotate the rotor 35 far enough torelease the ball 56 from its engagement with the shoulder 65, will thendraw the bolt 30 into the recess 67 in the strike member 66 and willfurther rotate the rotor 35 enough to move the ball 56 into engagementwith the shoulder 62. This will hold the bolt 30 in engagement with thestrike plate 66 until it is withdrawn therefrom by exerting a pull onlink 46.

An arrangement of the poles of magnets 36 and 68 which will bring aboutrotary and longitudinal movement of the bolt 30 and rotor 35 as aboveset forth is diagrammatically shown in FIG. 14. This figure shows thestrike magnet 68 as having on its front face a north pole at N and asouth pole at S and shows the rotor magnet 36 as having on the facethereof which is closest to the strike magnet when the door is closed anorth pole at N and a south pole at S. As the door 22 is moved toward aclosed position the two poles S and N, shown uppermost, will be closerto each other than the two lowermost poles N and S. Since all of thepoles are of about equal strength it is apparent that, as the door isbeing closed and is moved near to a closed position, the torque exertedon the rotor by the two uppermost poles S and N will hold the ball 56 inlocking engagement with the shoulder 65 until said two uppermost poles Sand N are substantially in alignment with each other. As soon as theuppermost pole S passes a 'position of true alignment with the uppermostpole N the direction of the torque exerted by these two poles S and N onthe rotor 35 will be reversed and will be in the same direction as thetorque that is then being exerted by the two lowermost poles N and S andthe rotor will be rotatively moved so as to release the ball 56 fromengagement with the shoulder 65 and align it with the part 63 oftrackway 20'. When this occurs the attraction between the two magnets 36and 68 will move the bolt 30 endwise into a locked position within thestrike plate opening 67. The torque being exerted on the rotor 35 by themagnet poles continues and when the ball 56 reaches the shoulder 62 itwill be moved into engagement with said shoulder 62 where it will remainuntil it is moved clear of said shoulder by the retraction of the pullback link 41.

When the bolt 30 is retracted by pull back link 41 in the act of openingthe door its retractile movement will be stopped by engagement of theball 56 with the curved wall of the enlarged end part 64 of trackway 20'and the ball 56 will be deflected sidewise into engagement with theshoulder 65 where it will remain and hold the bolt 30 retracted untilthe next closing movement of the door.

Briefly summarized the operation of this lock is as follows: When thedoor is closed magnetic flux will always move and tend to hold the boltin an outward position in engagement with the strike plate means and byrotatively moving the rotor member will engage the track follower withthe shoulder 62 and lock the bolt 30 in engagement with the strike platemeans. Manual retraction of the pull back link 41 will first unlock thetrack follower from the shoulder 62, then retract the bolt and allow thedoor to be opened. The curved wall of the terminal end part 64 of trackmember 20 and the small magnets 70 and 71 will cause the track followerto be locked and held in engagement with shoulder 65 until such time asthe rotor and strike members are moved into alignment With each other byclosing of the door, whereupon the dominant flux of the rotor and strikemagnets will unlock the track follower from the shoulder 65 snap thebolt 30 into the recess in the strike plate means and lock the trackfollower in engagement with the shoulder 62.

The foregoing description and accompanying drawings clearly disclosepreferred embodiments of my invention but it will be understood thatchanges may be made within the scope of the following claims.

I claim:

1. In latch and lock means for use in a door which is swingingly movablerelative to a door jamb, a tubular housing adapted to be installed in anedge portion of the door; a tubular bolt longitudinally movable in saidhousing between a retracted unlocked position and an outwardly projectedlocked position; manually operated bolt retracting means connected withsaid bolt; a magnetized strike member carried by the door jamb andhaving a bolt receiving recess positioned to receive said bolt; amagnetized rotor member disposed within and supported for limited rotarymovement by and movable longitudinally with said bolt; and meansoperated by limited rotary movement of said rotor member in said boltadapted to selectively lock said bolt either in a retracted or anoutwardly projected position, said rotor member and strike member beingmagnetized selectively and being positioned so that when the door withthe bolt in a retracted position is moved from an open to a closed doorposition in which the rotor member and strike member are in approximatealignment their magnetic flux will first rotatively move said rotor andunlock said bolt from its retracted position then longitudinally movesaid bolt into an outwardly projected position in engagement with saidstrike member and then further rotatively move said rotor and lock saidbolt in said outwardly projected position.

2. The lock and latch means as claimed in claim 1 in which the manuallyoperated bolt retracting means in cludes devices operative to firstrotatively move said rotor member and unlock the bolt from its outwardlyprojected position and to then longitudinally move said bolt to aretracted position.

3. The lock and latch means as claimed in claim 1 in which the means forselectively locking the bolt either in a retracted or in an outwardlyprojected position includes a longitudinally extending trackway in thehousing; two longitudinally spaced apart locking shoulders provided insaid trackway; and a track follower connected to and movable with saidrotor member operating in said trackway and movable into lockingengagement with each of said shoulders to selectively lock said bolt ineither a retracted or an outwardly projected position.

4. The latch and lock means as claimed in claim 2 in which the manuallyoperated bolt retracting means includes devices operable on initial boltretracting movement of the bolt retracting means in rotatively movingthe rotor member in the bolt and unlocking the track follower fromengagement with one of said locking shoulders and operable on furtherretraction thereof in retracting the bolt.

5. The latch and lock means as claimed in claim 2 in which at least oneholding magnet is attached to the housing adjacent the outer end thereofand positioned so its flux reacts with the flux of the magnetic rotormember in urging the track follower into engagement with the lockingshoulder by which the bolt is held retracted, the force exerted by saidmagnetic strike member dominating the force exerted by said holdingmagnet and releasing said track follower from engagement with saidshoulder when the rotor member is moved into approximate registrationwith the strike member.

6. Latch and lock means for use in a door which is movable relative to adoor jamb comprising a tubular housing adapted to be installed in theedge portion of the door, said housing having in its wall alongitudinally extending trackway provided with two spaced apart lockingshoulders, one of which is closer to the outer end of said housing thanthe other; a tubular bolt longitudinally movable in said housing betweena retracted and an out- Wardly projected position; bolt retracting meansconnected-with said bolt; a magnetized strike member in said jambpositioned to receive said bolt when said bolt is outwardly projected,said bolt having in its wall a transverse slot normally registering withthe trackway in said housing; a magnetized rotor member supported forlimited rotary movement in said tubular bolt, said rotor member having aperipheral wall portion close to the wall of said bolt and provided witha recess which normally registers with the transverse slot in saidtubular bolt and the trackway in said housing; and a track followerdisposed in the recess in said rotor member and extending through thetransverse slot in said bolt and into the trackway in said housing, saidtrack follower being movable along said trackway by longitudinalmovement of said rotor and bolt and being movable by rotary movement ofsaid rotor in said bolt into engaged and disengaged positions relativeto said locking shoulders, said track follower holding said boltretracted when it is engaged with the locking shoulder closest to theouter end of said housing and holding said bolt outwardly projected whenit is engaged with the locking shoulder farthest from the outer end ofsaid housing, said rotor and strike member being selectively magnetizedso as to provide between them a magnetic flux which, when the bolt isretracted and they are moved into approximate registration, with eachother by closing of the door will first rotatively move said rotor andrelease the track follower from the shoulder nearest the outer end ofthe housing, then move the bolt endwise to an outwardly projectedlocking position, then further rotatively move the rotor and engage saidtrack follower with the shoulder farthest from the outer end of saidhousing.

7. The latch and lock means as claimed in claim 6 in which an opening ofsubstantial size through which the track follower can be passed isprovided in the housing wall and a track extension along which the trackfollower can be moved connects said opening with the part of thetrackway between the two locking shoulders.

8. The latch and lock means as claimed in claim 6 in which the boltretracting means includes a manually operated pull back link and lostmotion devices connecting said pull back link with the rotor and thebolt, said lost motion devices being adapted, when moved by retractionof the pull back link, to first rotatively move the rotor in the boltand disengage the track follower from the locking shoulder nearest theouter end of the housing and then to move the bolt to a retractedposition.

References Cited UNITED STATES PATENTS 2,288,688 7/1942 Dubilier 2921443,107,934 10/1963 Lee 292- 3,208,782 9/1965 Zeller 292251.5 3,413,02611/1968 Kendrick et a1. 292-144 MARVIN A. CHAMPION, Primary Examiner R.L. WOLFE, Assistant Examiner US. Cl. X.R.

